Among the things confusing me about Mastodon: Is it federated for resilience and cost-sharing, so we're not all dependent on The Man at bird site? Or is it federated because it's supposed to be an alliance of close-knit communities? In other words, was I supposed to find the first Mastodon instance with vacancies that seemed reasonably well run (what I did), or was I supposed to find my tribe and sign up for a Mastodon instance that reflects my identity and values?